Internal-combustion engines and piston compressors often have leakage losses in practical use that can be traced to an incomplete seal. These leakage losses are called blowby gas and contain a considerable quantity of oil. The typical approach in terms of internal-combustion engines is therefore to pass the blowby gas accumulating on the camshaft back into the intake of the internal-combustion engine. A known approach for both minimizing the loss of oil caused by the blowby gas, and also to ensure optimal combustion and minimum pollution of the environment, is to have the blowby gas undergo an oil separation process and to return the separated oil back into the oil circuit. At the same time, the goal here is to design the corresponding oil separation systems to be as simple as possible, yet still reliable.
A hollow body in the form of a shaft having the above-described features has been disclosed in WO 2006/119737 [U.S. Pat. No. 7,717,101], where, in addition to a pre-separator disposed around the outer circumference of the shaft, a swirl generator integrated in the tubular section of the shaft is provided as the final separator. The oil separator must be designed so as to achieve a satisfactory separation of oil during both low and high volumetric flows of blowby gas.
In addition, oil separators are known that are installed outside the shaft, that is, outside a cylinder head cover holding a camshaft. Oil separators of this type, such as, for example, that described in DE 10 2004 006 082, are expensive to construct as separate physical units and require extra installation space.